Soil stabilization is the process of improving certain characteristics of soil through the addition of materials. It is most commonly used to increase the load bearing capability of soil and to harden it. This process results in a subbase and base course suitable for serving as a foundation for roads, parking lots, runways, driveways, and other pavement structures. A subbase may also be the top layer for certain footpaths or asphalt-free roads (often colloquially called “gravel roads.”)
Soil stabilization increases the soil strength, which increases the structural integrity of pavement placed on top of it, thereby lowering maintenance costs and maximizing the lifespan of the pavement.
Several types of materials may be used alone or in combination to stabilize the soil, depending on the natural characteristics of the soil itself and on the intended purpose of the final product. Among these compounds are Portland cement, lime, gypsum, fly ash, silica, bentonite and certain metal oxides. One common characteristics of these compounds is that they are dusty.
Often, the stabilizing compounds are loaded into a spreader truck, which deposits a layer of its contents as it drives over the work area. Additional material may then be laid, or otherwise processed.
Although the compounds may only drop several inches to the ground from the truck a large amount of dust can be generated. The dust is not only unsightly, but also difficult, and potentially hazardous, to breathe. Further, the dust that escapes is a loss of material that would otherwise be useful.
The invention of U.S. Pat. No. 4,990,025 uses water to prevent or reduce dust created by tilling soil while adding a stabilizing compound. In particular, it disclosed a system where by a tiller is tilling soil, while a truck containing water drives alongside the tiller, supplying it with water, and another truck containing a filler/binding material is also connected to the tiller and driving alongside it.
U.S. Pat. No. 4,061,221 discloses a flexible skirt that prevents dust from spreading until it is sucked into a collector.
Another dust-preventing flexible skirt is disclosed in U.S. Pat. No. 8,342,772. This design uses nested skirts to prevent dust from escaping and allowing it to settle to the ground.
U.S. Pat. No. 6,175,702 utilizes a vacuum system for eliminating dust in which a vacuum blower draws dusty air from a hood mounted near where the material is deposited and pulls this air though filter media contained in a dust collecting unit, resulting in cleaned air exiting the vacuum system, and in a rapidly filling, first-pass, dust collecting unit.